From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4CC4EC433F5 for ; Mon, 13 Sep 2021 10:43:09 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2118E60FF2 for ; Mon, 13 Sep 2021 10:43:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 2118E60FF2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-Id:Date:Subject:Cc :To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=zoLjoz2Ct4Ti1lbMDFohW4nY0rEB/w8/ICfwpEXsSzU=; b=Pwu/XS7efcZI2K Zz1kQL/dbAj8N47kYg7s/8cH32wkh0c/Rd29BsbddVgSROxLYsj7atUlP5aJQesozXZGM40SoV+m6 qC7qbaOKY/4vS5Gsw55aC6hgCqGVH2FblKiu7B8bgc06g53Ppm4mG1U40PY1PeqLciFZOD1je1D0C 8y7Hfa6ov1m4O39nppSPtRKpTUNQEGj9TRdscxEgMF8AZvByc42UEb5M9/E9q3fk2Yw/E+aw+7/q3 vZE0Xs6Y29/idheuO8L/lTnxguo9ReDa8eCOzPLT84yxDomaPYkUItvoOgNygePTUd4Srr4wHcpq2 TKtHH7M4ZuZZgXaLt4zQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mPjOF-001L1q-SK; Mon, 13 Sep 2021 10:40:44 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mPjO8-001L0L-VF for linux-arm-kernel@lists.infradead.org; Mon, 13 Sep 2021 10:40:39 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 70AF260F9B; Mon, 13 Sep 2021 10:40:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1631529636; bh=i4B2Ym+xx+fJ/CiwU/B2kVCfO9wqbCA2lzgPGDmQSzw=; h=From:To:Cc:Subject:Date:From; b=Gojn8S7qy6KM54N6Pn27atuczWyBhe+KLG7QoMtL9L6CiqAU90y6NiLuepwphqkS1 YjuzgCEl4xvzDM+sK3L9EZBLyacflu2TjuxCfqRCL79S47miTq1M2cg1QpE6NsWs0m CGxkZ7MbLW33eWOHGCsGiiQKEGw8qly345ehwuGQ5BzWpCLFQNHaL8xlp6NbBUINlR +jPnTgesUv35XBmuruPVfck568ygUSkkAblVMLVY8QznjCYSIXyOO96rvx45nJzVYN wMbiXYasZu+8okDtoPTQQHEcmDFl3nLfWaqZoOqTGj7aG0e4priNawgagU4khE1ko8 UJ42rKMIGFXlg== From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org Cc: Ard Biesheuvel , Keith Packard , Russell King , Kees Cook , Arnd Bergmann , Linus Walleij Subject: [PATCH v4 0/5] ARM: support THREAD_INFO_IN_TASK Date: Mon, 13 Sep 2021 12:39:56 +0200 Message-Id: <20210913104001.3043132-1-ardb@kernel.org> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210913_034037_093053_39998C72 X-CRM114-Status: GOOD ( 16.93 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Placing thread_info in the kernel stack leaves it vulnerable to stack overflow attacks. This short series addresses that by using the existing THREAD_INFO_IN_TASK infrastructure. This v4 is a follow-up to Keith's v3 [0], which did not address all concerns I raised in response to v2. After collaborating with Keith off-list, we decided that I should go ahead and post our joint v4. Changes since v3: - Leave the CPU field in thread_info, and keep it in sync at context switch time. This is by far the easiest and cleanest way to work around the fact that it is infeasible to implement raw_smp_processor_id() in terms of task_struct::cpu (for reasons of header soup). - Drop the VFP changes, they are no longer necessary given the previous point. - Drop the change to pass the CPU number to secondary_start_kernel(). Given that we also need to pass the idle task pointer, which carries the CPU number, passing the CPU number directly is redundant. - Use the TPIDRURO register to carry 'current' while running in the kernel, and keep using TPIDRPRW for the per-CPU offset as before. This way, there is no need to make any changes to the way the per-CPU offsets are programmed. It also avoids the concurrency issues that would result from carrying the 'current' pointer in a per-CPU variable. - Update the per-task stack protector plugin to pull the stack canary value directly from the task struct. Cc: Keith Packard Cc: Russell King Cc: Kees Cook Cc: Arnd Bergmann Cc: Linus Walleij [0] https://lore.kernel.org/all/20210907220038.91021-1-keithpac@amazon.com/ Ard Biesheuvel (4): gcc-plugins: arm-ssp: Prepare for THREAD_INFO_IN_TASK support ARM: smp: Free up the TLS register while running in the kernel ARM: smp: Store current pointer in TPIDRURO register if available ARM: smp: Enable THREAD_INFO_IN_TASK Keith Packard (1): ARM: smp: Pass task to secondary_start_kernel arch/arm/Kconfig | 8 ++- arch/arm/Makefile | 5 +- arch/arm/include/asm/assembler.h | 29 +++++++++++ arch/arm/include/asm/current.h | 51 ++++++++++++++++++++ arch/arm/include/asm/smp.h | 3 +- arch/arm/include/asm/stackprotector.h | 2 - arch/arm/include/asm/switch_to.h | 16 ++++++ arch/arm/include/asm/thread_info.h | 15 ++++-- arch/arm/include/asm/tls.h | 10 ++-- arch/arm/kernel/asm-offsets.c | 6 +-- arch/arm/kernel/entry-armv.S | 8 ++- arch/arm/kernel/entry-common.S | 1 + arch/arm/kernel/entry-header.S | 8 +++ arch/arm/kernel/head-common.S | 5 ++ arch/arm/kernel/head-nommu.S | 1 + arch/arm/kernel/head.S | 5 +- arch/arm/kernel/process.c | 8 +-- arch/arm/kernel/smp.c | 13 ++++- arch/arm/mm/proc-macros.S | 3 +- scripts/gcc-plugins/arm_ssp_per_task_plugin.c | 27 +++-------- 20 files changed, 173 insertions(+), 51 deletions(-) create mode 100644 arch/arm/include/asm/current.h -- 2.30.2 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel